diff --git a/requirements-dev.txt b/requirements-dev.txt
index dc28770..8bb7613 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -6,7 +6,7 @@ flake8==3.3.0
 # for compare script
 elasticsearch==5.3.0
 pytest==3.0.7
-pytest-cov==2.4.0
+pytest-cov==2.5.1
 pytest-aiohttp==0.1.3
 # pytest-sugar==0.8.0
 sphinx==1.5.5